Show them that not everything is serious buisness. Try to get people on TS when your server does karma trains or other funny stuff. They will come on their own when they see/hear that you can have alot of fun on TS too. People who are not regulars in WvW hear “come to TS for better organisation” that doesn’t really sound like alot of fun does it?
They probably have the image in mind that everyone is serious on TS with screaming commanders and if you dare to do something wrong hell breaks loose.
And don’t try to force microphones onto them some people just don’t want to talk. You better mention that when you advertise your TS that it is not a requirement to talk on TS.